I agree, that parents have the responsibility to keep their children reasonably behaved. Running up and down the aisles is unacceptable, of course. As is kicking the back of the chair in front, throwing things, screaming for no reason, etc. There are too many parents out there who refuse to discipline their children or recognize that their kid's behavior is unacceptable. These parents are usually spineless "don't want to emotionally scar my children" wimps, or are rude and clueless themselves.

That said, kids are kids. Even the most well-behaved children will act up occasionally and cause a scene, yell, cry, throw a tantrum, or just be generally upset. Sometimes it takes even the most considerate parents some time to calm their children or administer effective discipline. In a restaurant, parents have the ability to walk their kids out while doing this. Unfortunately, there is no such luxury in an airplane. And as for crying because of the pressure changes, drinking water/bottle helps but does not always do the trick. As long as the parents are being considerate and responsible in handling their children, the childless need to show some patience. Suggesting a minimum age for flying is ridiculous, however.

As for diaper changing, there is a line there. Changing a child on the seat right next to somebody is pretty rude, but if the family has the all the seats on that side of the row, where is the harm? I have done this myself (on my lap or on a changing pad, of course.) Would you rather them stay unchanged and smell the entire trip? Same for other public places. I have changed my child in the terminal rather than lug my carry-ons and 3-year old into the bathroom 100-yards down the terminal. I have also done this outside at Disney World on the stroller. Although in public view, I make sure to do this discreetly and privately as possible, not right next to somebody.

There has got to be a middle ground here based on consideration for other people and understanding of those with kids, and its a place I try to be.

Even if you are childless, you have to remember you were a child once too. And those with children have to realize that not everybody loves you child as much as you.